NEW YORK — With just days before he begins his term as New York City’s new mayor, Bill de Blasio (D) on Monday named longtime educator Carmen Fariña to lead the nation’s largest school system. The mayor-elect made the announcement at a press conference at Brooklyn’s William Alexander Middle School, where his two children attended.

The job gives Fariña, 70, a broad mandate to remake one of Mayor Michael Bloomberg’s signature sweeping changes to the city of New York.

Fariña, who met de Blasio early in his career, has long been the frontrunner for the job. A retired veteran educator, she most recently worked as deputy schools chancellor of New York City’s Department of Education under Bloomberg. In that capacity, she served as instructional chief, and she has been described as someone who connected teachers with Bloomberg’s technocrats and consultants.

Before that, Fariña taught in Brooklyn, worked as a principal in Manhattan and oversaw a group of schools as a regional superintendent. She was Chancellor Joel Klein’s No. 2, but would later come to criticize her boss’s policies.

Fariña met de Blasio in the 1990s, and reportedly helped the then-candidate craft much of his education platform.

Initially, Fariña told the New York City schools news site GothamSchools that she wasn’t interested in the job.

“Decided to spend this year as a full-time grandmother,” she wrote in an email. “Great unpaid job.” But in the weeks leading up to the announcement, she changed her tune, and the Times called her “the candidate who most closely matches de Blasio’s own thinking on education.”

Fariña will face the daunting task of presiding over the city’s largest agency while wedding de Blasio’s education campaign promises with the city’s fiscal and political realities. Fariña will contend with a skeptical teaching force that has seen many sudden changes over the last decade. She will have to combat what de Blasio has called a “broad negative attitude toward teachers” while negotiating against the United Federation of Teachers union to renew a contract that is four years overdue. On the teaching and learning side, Fariña must oversee the implementation of the Common Core State Standards, a major pedagogical shift.

Just as so-called education reformers throughout the country look to New York as a signal of what advancements they could realistically expect from urban school systems, many critics are expecting the de Blasio administration to be a bellwether for how quickly and easily these polarizing changes can be knocked down.

Bloomberg’s three terms in office were marked by major, business-like developments to the 1.1 million-student school system — developments that technocrats like Bloomberg embraced as a welcome disruption to a staling bureaucracy, but that the teachers union and some parents decried as “corporate reforms” that took the magic out of education by running schools like big companies. Notably, Bloomberg persuaded the state house to give him authority over the schools, a process known as mayoral control. He took a total outsider — antitrust attorney Joel Klein — and named him schools chancellor. Together, they sparred with the union over the way teachers are assigned and evaluated. They promoted a teacher evaluation system that relied, in part, on student test scores, and made it much harder for new teachers to get tenure.

Bloomberg and Klein also instituted a letter-grading system to rate schools in accordance with several empirical factors, including performance on standardized tests. These grades determined each school’s fate, and in some cases led to closure and replacement with newer, smaller schools. Some were charter schools, which receive public funds but can be privately run. They also boosted charter schools by offering space in public school buildings rent-free, a policy that has irked critics, who say it created a two-tiered school system.

On Nov. 25, de Blasio told reporters he’d have chancellor news “in a couple more days down the road.” But a month later, there was still no chancellor. As GothamSchools reported, de Blasio’s transition team was spinning the long process as evidence of the new mayor’s care in selecting the perfect fit for such a crucial position.

But others have said the public fits and starts are evidence of either Team de Blasio’s lack of discipline, or, more plausibly, an inability to find a candidate who shares his educational philosophies and has experience managing a large-scale, urban school system. Over the last few weeks, sources have told HuffPost that candidates such as Washington, D.C., Chancellor Kaya Henderson and Chicago Public School’s leader Barbara Byrd-Bennett were under consideration — but Henderson said she wanted to stay in the capital, and Byrd-Bennett recently unveiled a new Chicago initiative. Both have been involved with policies de Blasio staunchly opposes, such as school closures.

De Blasio campaigned on reversing Bloomberg’s reforms, making education a major part of his “tale of two cities” populist bid for the job. He pushed an agenda that would create a system of universal pre-kindergarten slots for the city’s tiniest learners, critiqued the Bloomberg administration’s scores of school closures and railed against the policy of giving charter schools free space.

“There’s no way in hell Eva Moskowitz should get free rent, okay?” de Blasio said at a forum in June. Moskowitz is the high-profile creator of Success Academy, a fast-growing chain of charter schools that has become emblematic of the Bloomberg years.

Because of Bloomberg’s successful fights in Albany for mayoral control — one Bloomberg change the new mayor has embraced — de Blasio will theoretically have unprecedented power to remake the nation’s largest public school system.

“There’s a real fault line between the first Bloomberg term and the second two. That’s why you hear such a critique,” de Blasio told HuffPost in an interview early in his campaign. “The first term, they achieved mayoral control … You had some real atmosphere of reform, some visible progress … I think the first Bloomberg term had a lot of promise to it. Lately it’s marked by constant conflict with parents and teachers, obsessive interest in closing schools, concerns about teaching to the test, moving away from early childhood education.” Overall, the last two terms, he said, were “profoundly disappointing.”

De Blasio’s son, Dante, who was featured in a campaign advertisement, attends public school. “This is very personal,” de Blasio said at the time. “There’s been a real sense of lost opportunity, mixed with an increasingly divisive approach.”

The controversial role of standardized testing also stands to change in the new administration. In the HuffPost interview, de Blasio said that some testing is necessary — as required by federal law — but the Bloomberg administration focused on it too much.

“I’m a big fan of not using a single point of standardized tests for teacher evaluations, but focusing on portfolio assessments,” de Blasio said. “You can do that by looking at student work. I’d like to see us moving more formally there.”

More recently, the transition team said de Blasio would figure out the charter school rent question once his administration takes office, but previously, de Blasio has proposed “a sliding scale.”

“Free rent was not a guarantee, it’s contextual,” de Blasio told HuffPost. “A school that needs it and can perform well, yeah, but treat charters the way you treat traditional public schools. Within the larger charter discussion, I’m not anti-charter, I believe charters have a role to play.”